On Fri, 2023-06-30 at 11:34 +0200, Peter Zijlstra wrote: > On Thu, Jun 29, 2023 at 09:15:39AM +0000, Huang, Kai wrote: > > > Sure. How about below? > > > > + /* > > + * TDH.SYS.INFO writes the TDSYSINFO_STRUCT and the CMR array > > + * to the buffers provided by the kernel (via RCX and R8 > > + * respectively). The buffer size of the TDSYSINFO_STRUCT > > + * (via RDX) and the maximum entries of the CMR array (via R9) > > + * passed to this SEAMCALL must be at least the size of > > + * TDSYSINFO_STRUCT and MAX_CMRS respectively. > > + * > > + * Upon a successful return, R9 contains the actual entries > > + * written to the CMR array. > > + */ > > sysinfo_pa = __pa(sysinfo); > > cmr_array_pa = __pa(cmr_array); > > ret = seamcall(TDH_SYS_INFO, sysinfo_pa, TDSYSINFO_STRUCT_SIZE, > > > Or should I just repeat the spec like below? > > > + /* > > + * TDH.SYS.INFO writes the TDSYSINFO_STRUCT and the CMR array > > + * to the buffers provided by the kernel: > > + * > > + * Input: > > + * - RCX: The buffer of TDSYSINFO_STRUCT > > + * - RDX: The size of the TDSYSINFO_STRUCT buffer, must be at > > + * at least the size of TDSYSINFO_STRUCT > > + * - R8: The buffer of the CMR array > > + * - R9: The entry number of the array, must be at least > > + * MAX_CMRS. > > + * > > + * Output (successful): > > + * - RDX: The actual bytes written to the TDSYSINFO_STRUCT > > + * buffer > > + * - R9: The actual entries written to the CMR array. > > + */ > > sysinfo_pa = __pa(sysinfo); > > cmr_array_pa = __pa(cmr_array); > > ret = seamcall(TDH_SYS_INFO, sysinfo_pa, TDSYSINFO_STRUCT_SIZE, > > Either of them work for me, thanks! I will choose the first one since it's shorter. Thanks! > > > > SDM doesn't seem to be the place. That doesn't > > > even list TDCALL/SEAMCALL in Volume 2 :-( Let alone describe the magic > > > values. > > > > > > > TDX has it's own specs at here: > > > > https://www.intel.com/content/www/us/en/developer/articles/technical/intel-trust-domain-extensions.html > > > > For this one you can find it in here: > > > > https://cdrdv2.intel.com/v1/dl/getContent/733568 > > Yeah, eventually found it. I still think both TDCALL and SEAMCALL should > be listed in SDM Vol.2 instruction listing -- every valid instruction > should be found there IMO. > > I also feel strongly that a global ABI should be decided upon for them > and the SDM would be a good place to mention that. leaving this to > individual calls like now is a giant pain in the rear. Yeah I agree how the specs are organized is not ideal. We have been having pain during our development too. > > As is, we have TDCALL leaf-0 with a giant regset but every other leaf > has (c,d,8,9) for input and +(10,11) for output. Lets fix that in stone. > > Obviously I also very strongly feel any such ABI must not confict with > pre-existing calling conventions -- IOW, using BP is out, must not > happen. Fully agreed.
